Avalanche Forecast
Issued: Jan 14th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Persistent Slabs.
kdevine,
Avalanche Canada
Human triggered avalanches remain likely as strong winds are expected to form fresh slabs throughout the day. Look for low-angle, sheltered slopes for the best, and safest riding.
Summary
Confidence
Moderate - Uncertainty is due to the limited number of field observations. Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
THURSDAY NIGHT - Mainly clear / light to moderate northwest wind / alpine low temperature near -6Â
FRIDAY - Sunny with cloudy periods / strong west wind / alpine high temperature near -4 / freezing level 1500 m
SATURDAY - A mix of sun and cloud / light to moderate west wind / alpine high temperature near -7Â
SUNDAY - Mainly cloudy with sunny periods and isolated flurries / strong west wind / alpine high temperature near -5
Avalanche Summary
With strong west winds in the forecast and a lot of fresh snow available to blow around, storm and wind slabs are expected to be easy to trigger on Friday, especially in wind loaded areas.
There was one size 3 persistent slab avalanche reported on an east aspect at 2400 m in the neighboring Waterton National Park region on Thursday.
There were several natural and explosives triggered avalanches up to size 2.5 reported in the region on Wednesday.
A large (size three) cornice triggered persistent slab avalanche was reported on a large south-facing alpine slope in the Crowsnest Pass area last Thursday. This avalanche failed on weak facets overlying a hard crust deep in the snowpack and is an example of the "low probability; high consequence" scenario that persistent slab problems often create. View the MIN report HERE.
Snowpack Summary
The region received 15-30 cm of new snow between Tuesday night and Wednesday with strong to extreme wind.
The lower snowpack consists of decomposing crusts and weak, faceted snow. In the Elk Valley, a decomposing surface hoar layer can be found around one of these crusts 60-120 cm below the surface. Avalanche activity on these layers in the lower snowpack has been sporadic, mostly triggered by large loads such as a wind slab avalanche, or a cornice fall. These deeper weak layers are most likely to be human triggered on steep, rocky slopes with a shallow or thin to thick snowpack.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Avoid freshly wind loaded terrain features.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Minimize exposure to steep, sun exposed slopes, especially when the solar radiation is strong.
Problems
Storm Slabs
Up to 30 cm of snow fell recently in the region. With ongoing strong winds, fresh slab formation is likely still occurring. These slabs will be easiest to trigger in wind loaded areas.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Triggering large avalanches on weaknesses in the lower snowpack remains a possibility, especially since the new snow has added load to these weak layers. In some areas the concern is weak snow around crusts 60 to 120 cm deep, while in others it's weak snow near the bottom of the snowpack. Human triggering of these layers are most likely in steep, rocky slopes with a shallow or thin to thick snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 15th, 2021 4:00PM
